Combustion apparatus



2 Sheets-Sheet l INVENTOR (2 15 A TTORNEV March 13, 1934. R. A. FORESMAN COMBUSTION APPARATUS Filed Oct. 16, 1931 FEQBEQT H-FORESMRN.

March 13, 1934. R. A. FORESMAN COMBUSTION APPARATUS Filed Oct. 16, 1931 2 Sheets-Sheet 2 0 N0 0 o o o o o o o INVENTOR RoaERT H. Fonasmmv ATTORNEY Patented Mar. 13, I934 UNITE STATES PATENT,

' PFIE COMBUSTION APPARATUS Application October 16,

3 Claims.

My invention relates to combustion apparatus and particularly to combined underfeed-overfeed stoker apparatus having a clinker grinder pit disposed at the lower discharge end thereof, and it has for a broad object to provide apparatus of this character which is of improved construction and arrangement of parts.

In this type of apparatus it is always desirable to obtain with the proper efficiency the greatest possible furnace rating for each square foot of horizontal projected furnace area. In other words it is desirable that the combustion equipment release the maximum amount of heat for the amount of floor space occupied thereby.

In apparatus of this character heretofore known to me the clinker pit is disposed vertically and therefore occupies as much of the horizontal projected area of the furnace as is possible. Furthermore, a relatively poor rate of combus- 99 tion is carried on in the horizontal space occupied by the clinker pit due to the fact that there is a relatively small percentage of combustible matter in the material and also to the fact that the air necessary for combustion cannot easily penetrate the material. Also, in prior apparatus it is the usual practice to carry a large head of relatively cool ash directly above the clinker rolls for the dual purpose of protecting the rolls and preventing the infiltration of outside air into i) the pit and furnace. This head of ash furnishes an additional obstacle to the free flow of air and thereby lowers further the rate of combustion carried on in the clinker pit.

It is, therefore, a more specific object of the 85 present invention to provide an improved form of combustion apparatus, by means of which it is possible to materially increase the rate of combustion carried on in that portion of the horizontal projected area of the furnace usually 4 occupied by the clinker pit, and also, the head of cooling and sealing ash heretofore found necessary is no longer needed.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

- Fig. 1 is a fragmentary vertical longitudinal sectional view taken through my improved form of combustion apparatus.

Fig. 2 is a horizontal sectional view taken on the line 11-11 of Fig. l.

. According to a specific embodiment of the present invention I provide a downwardly-inclined multiple-retort under-feed section; a downwardly-inclined overfeed section having its upper end disposed to receive the material discharged from the lower end of the underfeed section and comprising a series of pivotally connected grate bars extending in the direction of fuel feed, with 1931, Serial No. 569,344

means for imparting angular movement to certain of the grate bars so as to effect agitation and translation of the fuel bed carried thereby; and a clinker pit disposed to receive the material from the overfeed section and comprising a front wall inclined downwardly with respect to the horizontal and at a greater angle than that of the overfeed section, a rear Water wall inclined in a similar manner to the front wall, upright end walls, grinder mechanism disposed in the lower portion of the pit and at least partially, submerged in water; the front wall of the pit including a series of pivotally connected grate bars connected at their upper ends to the end of the series comprising the overfeed section and being supported for longitudinal movement in the direction of fuel travel.

By reason of this construction, the air-emitting and agitating grates forming for the most part the front wall of the clinker pit comprise approximately that portion of the horizontal projected area of the furnace which is occupied by the clinker pit. I-Ience, relatively large rates of combustion can be carried on in this portion of the area, and, therefore, the combustion rate for the furnace is materially increased. In this construction the sealing and cooling head of ash is not necessary as the grinder rolls are submerged in water. Furthermore, the horizontally projected area occupied by the rear wall of the clinker pit is outside the furnace and is below the operating floor, Where horizontal space is not at such a premium.

Referring now in detail to the construction illustrated, the reference numeral 10 indicates in its entirety a furnace including a front wall 11, a rear wall 12 and side walls 13. A progressive feed stoker 14. is disposed within the furnace and divides the latter into a combustion chamber 15 and an air chamber or wind box 16.

The progressive feed stoker comprises a downwardly-inclined multiple retort underfeed section 1'7, into which coal is fed from a hopper 18 by means of primary rams 19 and advanced along the retorts by means of secondary rams 20.

The stoker also comprises a downwardly-inclined overfeed section 22 consisting of a series of grate members 23 pivotally connected together in end-to-end relation and extending in the direction of fuel feed. The series is pivotally anchored at its forward end as indicated at 24 to a stationary part 25 of the stoker structure. Angular movement is imparted to certain of the grate members by means of links 26 carried by the outer ends of lever arms 2'? which are in turn keyed to a rock shaft 28. The rock shaft 28 is adapted to be operated by means of a suitable motor reduction gear unit 29. The remaining grate members of the series are supported for bodily movement in the direction of fuel feed by means of pivoted links 30 fastened at their lower ends to stationary part of the stoker structure.

A clinker pit 31 is disposed at the lower discharge end of the overfeed section and comprises a front wall 32 inclined downwardly with respect to the horizontal, a rear wall 33 formed of water circulating tubes 34 which may be covered by suitable refractory material, upright end walls 35, and grinder rolls 36 disposed in the lower portion thereof for supporting and gradually removing the material from the pit.

An ash pit 37 is disposed beneath the grinder rolls and the walls thereof are in efiect continuations of the clinker pit walls. A body of water is provided within the ash pit with the upper level thereof above the grinder rolls. The water performs the dual purpose of maintaining a water seal for the lower portion of the clinker pit and for protecting the rolls from the destructive action of the burning material in the pit.

It is observed that the front wall of the pit is composed for the most part of a series of grate members 38 of substantially the same construction as the grate members forming the overfeed section. The upper end of the series of grate members 38 is pivotally connected to the lower end of the series 23 forming the overfeed section. The grates forming the series are supported for bodily movement by links 40 pivotally connected thereto and also to suitable stoker supporting structure. The arcuate movement at the points of comiection with the grate also provides a certain amount of angular movement to the grates. It is apparent that the front wall of the clinker pit is in effect a continuation of the overfeed grate section and that due to the motion imparted thereto by virtue of its connection with the overfeed section, any combustible material resting on or above such wall will be readily burned.

From an examination of the drawings it will be readily seen that the horizontally projected area of the stoker and the front wall of the pit are substantially the same as the horizontal area of the furnace chamber at the floor line. Thus, substantially all of the furnace area is provided with active grate surface and the maximum combustion rate can be obtained in this area. It is true that due to the inclination of the pit the back Wall 33 extends beyond the rear wall 12, but as this is below the floor line where horizontal space is not at such a premium, no disadvantage is realized.

The rolls 36 are operated so as to keep very little ash in the pit, and thereby eliminate interference with combustion from this score. This is rendered possible by submerging the grinder rolls at least partially in water. As the rear wall 12, is water cooled its surface is protected and therefore active combustion in the pit will do substantially no damage thereto.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, Without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In combustion apparatus, the combination of a downwardly-inclined multiple-retort underfeed stoker section; a downwardly-inclined overfeed stoker section disposed at the lower or discharge end of the underfeed section and com-' prising a series of pivotally connected grate bars extending in the direction of fuel travel; means for imparting angular movement to certain of the grate bars so as to provide for agitation and feeding of the fuel bed carried thereby; and a clinker pit disposed to receive the material from the lower or discharge end of the overfeed section and comprising a front wall also inclined downwardly with respect to the horizontal and at a substantially greater angle than that of the overfeed section, a rear wall inclined in a direction similar to the front wall, and grinder mechanism disposed in the lower portion of the pit and being at least partially submerged in Water; the front wall of the pit comprising a series of pivotally connected grate bars extending in the direction of fuel travel and pivoted at its upper end to the lower end of the series of grate bars forming the overfeed section and the grate bars of the clinker pit being supported for reciprocating motion in the direction of fuel feed.

2. In combustion apparatus, the combination of a downwardly-inclined multiple-retort underfeed stoker section; a downwardly inclined overfeed stoker section disposed at the lower or discharge end of the underfeed section and comprising a series of pivotally connected grate bars extending in the direction of fuel travel; means for imparting angular movement to certain of the grate bars so as to provide for agitation and feeding of the fuel bed carried thereby; and a clinker pit disposed to receive the material from the lower or discharge end of the overfeed section and comprising a front wall inclined downwardly with respect to the horizontal and at a substantially greater angle than that of the overfeed section, a water-cooled rear wall inclined in a direction similar to the front wall, and grinder mechanism disposed in the lower portion of the pit and being at least partially submerged in water; the front wall of the pit comprising a series of pivotally connected grate bars extending in the direction of fuel travel and pivoted at its upper end to the lower end of the series of grate bars forming the overfeed section and the grate bars being supported for reciprocating motion in the direction of fuel feed.

3. In combustion apparatus, the combination of a downwardly-inclined multiple-retort underfeed stoker section; a downwardly-inclined overfeed stoker section disposed at the lower or discharge end of the underfeed section and comprising a series of pivotally connected grate bars extending in the direction of fuel travel; means for imparting angular movement to certain of the grate bars so as to provide for agitation and feeding of the fuel bed carried thereby; and a clinker pit disposed to receive the material from the lower or discharge end of the overfeed section and comprising a front wall also inclined downwardly with respect to the horizontal and at a substantially greater angle than that of the overfeed section, a rear Wall, upright end walls, and grinder mechanism disposed in the lower portion thereof; the front wall of the pit comprising a series of pivotally-connected grate bars extending in the direction of fuel travel and pivoted at its upper end to the lower end of the series of grate bars forming the overfeed section and the grate bars of the clinker pit being supported for reciprocating motion in the direction of fuel feed.

ROBERT A. FORESMAN. 

